This invention relates generally to the cloning and identification of novel outer membrane proteins of several strains of Neisseria, and more specifically to proteins useful in the prevention, therapy and/or diagnosis of infection and diseases in mammals caused by these strains.
The pathogenic Neisseriae cause several important non-symptomatic infections and symptomatic diseases in humans. Neisseria gonorrhoeae is the agent of non-symptomatic gonococcal infection or symptomatic disease, i.e., gonorrhea. Neisseria meningitidis is the agent of a rapidly progressive spinal meningitis, which may also have a non-symptomatic infective stage. The surfaces of such pathogens provide crucial interfaces for interactions between the pathogen and the host. Many bacterial virulence factors are outer membrane proteins, and surface exposed proteins are the primary targets recognized and attacked by the host's immune system. Thus, the role of outer membrane proteins is of particular importance in understanding the pathogenesis of these organisms. The most abundant and immunodominant outer membrane proteins of the pathogenic Neisseriae have been studied extensively (Sparling P. F. et al, Clin. Invest., 89: 1699-1705 (1992)). For example, it is known that the immunodominant components of the gonococcal surface are antigenically variant, suggesting that this organism is capable of adapting to varying host environments while avoiding host immune responses. Although the major gonococcal surface proteins have been extensively studied, little is known about less abundant proteins and their contributions to pathogenesis.
Two-dimensional electrophoresis (IEF and SDS-PAGE) of labeled, e.g., radioiodinated or biotinylated, gonococcal surface proteins suggested that numerous (>20) of the less abundant gonococcal outer membrane proteins remained uncharacterized (unpublished observations). Among these might be proteins which play an important role in infection.
For example, surface-exposed outer membrane proteins of other microorganisms, e.g., Haemophilus influenzae D15 surface antigen (D-15-Ag) and the Pasteurella multocida Oma87, have been found to be useful in eliciting antibodies that were protective against infectious challenge in animal models. The Omp85-like D-15-Ag was conserved in both non-typeable and typeable strains of H. influenzae and was recognized by convalescent patient sera; affinity-purified anti-D-15-Ag serum was protective in the rat pup model (Thomas, W. R., et al, Infect. Immun., 58:1909-1913 (1990); Flack, F. S. et al, Gene, 156:97-99 (1995)]). H. influenzae serotypes a-f, nontypeable H. influenzae and Haemophilus parainfluenzae all expressed proteins similar to the D-15-Ag, as demonstrated by immunoblot analysis. Antibodies to recombinant D-15-Ag protected against H. influenzae type b and type a bacteremia in the infant rat model (Loosmore, S. M. et al, Infect. Immun., 65:3701-3707 (1997)).
Like H. influenzae D-15-Ag, the Oma87 of P. multocida was highly conserved among strains and was recognized by protective antibody; it was present in all 16 serotypes of P. multocida and was recognized by convalescent animal sera. Antibodies raised to recombinant Oma87 were protective against homologous challenge in the mouse model (Ruffolo, C. G. et al., Infect. Immun., 64:3161-3167 (1996)). Despite the several publications describing the immunological properties of D-15-Ag and Oma87, the function of these proteins remains unknown.
There remains a need in the art for the development of proteins from Neisseriae which are useful in research, diagnosis and treatment of the infections, especially non-symptomatic infections, and the diseases caused by these pathogens.